Nonaqueous, liquid depolarizer, high rate discharge, primary batteries are similar in many respects to other primary batteries, they comprise at least one high rate discharge cell, with each cell comprising an anode, a cathode current collector, a separator between the anode and the cathode current collector, and a substance which is both a nonaqueous liquid depolarizer and an electrolyte solvent. The liquid depolarizer in high rate batteries is in direct contact with the anode, as opposed to conventional cells where the anode and cathode depolarizer must be physically separated.
When a high rate primary cell, as any electrochemical cell, produces electrical energy it also produces heat. Heat is generated within the cell at a site of heat generation. The main site of heat generation is located at the point where the chemical reaction producing the electrical energy occurs, in a high rate cell this point is where the liquid cathode contacts the anode and the cathode current collector. Heat is also generated in the electrolyte and in all of the electrically conductive elements of the cell by ohmic heating.
In small, low capacity cells and batteries, the heat generated is minute and easily dissipated into the environment. As batteries become larger and increase in capacity, the heat generated increases and becomes more of a problem. In liquid depolarizer, high rate primary batteries, such as those with a capacity of from 100 ampere hours to 10,000 ampere hours or more, the problem becomes critical. Unless the heat of reaction generated by the primary battery can be removed quickly and in sufficient amounts, thermal runaway may occur with disastrous results.